According to North American Numbering Plan, 773660 located in CHICAGO, Illinois. the first three digits 773 locate to state Illinois, 660 locate the city CHICAGO, furthermore, we also provide some other information such as the zip code example(s) 60628, 60643, 60827, carrier AMERITECH ILLINOIS, and the latitude and longitude is 41.6877 -87.6305. Please pay attention that the detail we provide only as a reference, the details of the zip code may be not complete, the latitude and longitude likely to have deviation.